In a typical advanced request routing service, such as a load balancer, when a client initiates a connection request it is accepted by the request router. The client then follows up with the request data, the request router looks at the data, and based on the request data, the request router requests the actual content from a different (target) server. In this case, the request router is in the middle of the communications path back to the client. Consequently, all of the data that needs to go back to the client is routed from the target server through the request router.
This creates unnecessary network activity in many scenarios. In some cases the request router actually needs to look at the return data to cache the return data or process the data in other ways. However, in many cases, this traffic is completely unnecessary, as this approach consumes more network and network device bandwidth unnecessarily.